A few users have reported that they are redirected and logged out as soon as they login. Try logging in using a different browser (Internet Explorer, Chrome, Firefox, Safari, etc.). If you are able to login, the problem is with the cookies stored by the browser that logs you off. Using the browser that logs you off, locate the text at the bottom right of the forum page that is labled "Delete all board cookies". Click it and you should then be able to login.